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File: includes/getid3/extension.cache.dbm.php

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  Classes of Karl Holz  >  WaldScan  >  includes/getid3/extension.cache.dbm.php  >  Download  
File: includes/getid3/extension.cache.dbm.php
Role: Auxiliary script
Content type: text/plain
Description: getID3 dependency
Class: WaldScan
Scan directories for files with certain extensions
Author: By
Last change:
Date: 1 year ago
Size: 5,902 bytes
 

Contents

Class file image Download
<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
//                                                             //
// extension.cache.dbm.php - part of getID3()                  //
// Please see readme.txt for more information                  //
//                                                            ///
/////////////////////////////////////////////////////////////////
//                                                             //
// This extension written by Allan Hansen <ahŘartemis*dk>      //
//                                                            ///
/////////////////////////////////////////////////////////////////


/**
* This is a caching extension for getID3(). It works the exact same
* way as the getID3 class, but return cached information very fast
*
* Example:
*
*    Normal getID3 usage (example):
*
*       require_once 'getid3/getid3.php';
*       $getID3 = new getID3;
*       $getID3->encoding = 'UTF-8';
*       $info1 = $getID3->analyze('file1.flac');
*       $info2 = $getID3->analyze('file2.wv');
*
*    getID3_cached usage:
*
*       require_once 'getid3/getid3.php';
*       require_once 'getid3/getid3/extension.cache.dbm.php';
*       $getID3 = new getID3_cached('db3', '/tmp/getid3_cache.dbm',
*                                          '/tmp/getid3_cache.lock');
*       $getID3->encoding = 'UTF-8';
*       $info1 = $getID3->analyze('file1.flac');
*       $info2 = $getID3->analyze('file2.wv');
*
*
* Supported Cache Types
*
*   SQL Databases:          (use extension.cache.mysql)
*
*   cache_type          cache_options
*   -------------------------------------------------------------------
*   mysql               host, database, username, password
*
*
*   DBM-Style Databases:    (this extension)
*
*   cache_type          cache_options
*   -------------------------------------------------------------------
*   gdbm                dbm_filename, lock_filename
*   ndbm                dbm_filename, lock_filename
*   db2                 dbm_filename, lock_filename
*   db3                 dbm_filename, lock_filename
*   db4                 dbm_filename, lock_filename  (PHP5 required)
*
*   PHP must have write access to both dbm_filename and lock_filename.
*
*
* Recommended Cache Types
*
*   Infrequent updates, many reads      any DBM
*   Frequent updates                    mysql
*/


class getID3_cached_dbm extends getID3
{

    
// public: constructor - see top of this file for cache type and cache_options
    
function getID3_cached_dbm($cache_type$dbm_filename$lock_filename) {

        
// Check for dba extension
        
if (!extension_loaded('dba')) {
            throw new 
Exception('PHP is not compiled with dba support, required to use DBM style cache.');
        }

        
// Check for specific dba driver
        
if (!function_exists('dba_handlers') || !in_array($cache_typedba_handlers())) {
            throw new 
Exception('PHP is not compiled --with '.$cache_type.' support, required to use DBM style cache.');
        }

        
// Create lock file if needed
        
if (!file_exists($lock_filename)) {
            if (!
touch($lock_filename)) {
                throw new 
Exception('failed to create lock file: '.$lock_filename);
            }
        }

        
// Open lock file for writing
        
if (!is_writeable($lock_filename)) {
            throw new 
Exception('lock file: '.$lock_filename.' is not writable');
        }
        
$this->lock fopen($lock_filename'w');

        
// Acquire exclusive write lock to lock file
        
flock($this->lockLOCK_EX);

        
// Create dbm-file if needed
        
if (!file_exists($dbm_filename)) {
            if (!
touch($dbm_filename)) {
                throw new 
Exception('failed to create dbm file: '.$dbm_filename);
            }
        }

        
// Try to open dbm file for writing
        
$this->dba dba_open($dbm_filename'w'$cache_type);
        if (!
$this->dba) {

            
// Failed - create new dbm file
            
$this->dba dba_open($dbm_filename'n'$cache_type);

            if (!
$this->dba) {
                throw new 
Exception('failed to create dbm file: '.$dbm_filename);
            }

            
// Insert getID3 version number
            
dba_insert(getID3::VERSIONgetID3::VERSION$this->dba);
        }

        
// Init misc values
        
$this->cache_type   $cache_type;
        
$this->dbm_filename $dbm_filename;

        
// Register destructor
        
register_shutdown_function(array($this'__destruct'));

        
// Check version number and clear cache if changed
        
if (dba_fetch(getID3::VERSION$this->dba) != getID3::VERSION) {
            
$this->clear_cache();
        }

        
parent::getID3();
    }



    
// public: destuctor
    
function __destruct() {

        
// Close dbm file
        
dba_close($this->dba);

        
// Release exclusive lock
        
flock($this->lockLOCK_UN);

        
// Close lock file
        
fclose($this->lock);
    }



    
// public: clear cache
    
function clear_cache() {

        
// Close dbm file
        
dba_close($this->dba);

        
// Create new dbm file
        
$this->dba dba_open($this->dbm_filename'n'$this->cache_type);

        if (!
$this->dba) {
            throw new 
Exception('failed to clear cache/recreate dbm file: '.$this->dbm_filename);
        }

        
// Insert getID3 version number
        
dba_insert(getID3::VERSIONgetID3::VERSION$this->dba);

        
// Re-register shutdown function
        
register_shutdown_function(array($this'__destruct'));
    }



    
// public: analyze file
    
function analyze($filename) {

        if (
file_exists($filename)) {

            
// Calc key     filename::mod_time::size    - should be unique
            
$key $filename.'::'.filemtime($filename).'::'.filesize($filename);

            
// Loopup key
            
$result dba_fetch($key$this->dba);

            
// Hit
            
if ($result !== false) {
                return 
unserialize($result);
            }
        }

        
// Miss
        
$result parent::analyze($filename);

        
// Save result
        
if (file_exists($filename)) {
            
dba_insert($keyserialize($result), $this->dba);
        }

        return 
$result;
    }

}


?>